Switches are used in electrical applications to selectively provide an electrical connection between two or more terminals of a switch. Power switches are used in applications where high voltages have to be switched and/or high currents have to be conducted via the switch, for example voltages of some hundred Volts and currents of several Amperes, for example several tens of Amperes. Such switches may inter alia be used in safety-critical environments, for example in automotive applications. In such environments, besides the “pure” function of a device like a switch (i.e. selectively providing an electrical connection), functional safety aspects become more and more important, for example in automotive applications in the power transmission chain, braking, engine management etc.
For example, according to some functional safety requirements, for a specific function there may have to be alternative ways to achieve this function, and/or a safe switch-off path to deactivate the function. For example, to achieve this, redundancy may be provided, for example alternative connections between devices, or different ways to achieve a function may be provided, which is an example for diversification (sometimes also referred to as diversity). To give an example, in conventional systems to control a switch or combination of switches (for example arranged in a half bridge topology), in some applications two signal paths are required: one to define a switching behaviour of the switch (for example by providing a pulse width modulated (PWM) signal), and another one to enable/disable the operation of the switch or combination of switches. These two signals are generated and provided by different paths. For example, a pulse width modulated signal may use a path through some logic blocks and a gate driver, whereas the enable signal interacts with the gate drive very closely for the switch.
Nevertheless, the two signals in conventional approaches are combined at some point, for example in a logic circuit or at a gate driver, to provide a single control signal to the switch. Therefore, at least in part of a circuit there is only a single connection to the switch (for example from the gate driver to the switch), for which no redundancy is provided.